Recently 5.0.0.348 for the BlackBerry Bold 9000 was leaked. I installed this on my BlackBerry and all was well, until I traveled to the US and put my AT&T SIM card into the device. It then gets into a reboot cycle the minute a network connection is established. I am speculating that something in the AT&T service books is causing the device to reboot. Potentially their service books are not updated to work with this version of OS5 on the Bold.